I went through the Yale ones a couple of years ago, and would highly recommend them if you've got a spare 20 hours coming up. The exam questions (especially Caleb and his fear of clowns) are also worth a look over.
I've actually learned about game theory by watching this exact lecture series (ECON 159) online on my own and I will recommend this to anyone. It doesn't require anything except for basic algebra and, later on, some basic economics.
It's worth adding that you'll probably get more out of it if you have more maths than this. There are a couple of examples of optimisation with basic calculus to find mixed strategy Nash Equilibria, for example, but the course is clearly aimed at an interdisciplinary audience, so it's possible to just take the maths as given.
Reading the What topics would you like to see more of on LessWrong? thread gave me the impression that many people here would appreciate introductory material to several of the topics that are often discussed in lesswrong. I have therefore decided to link in the direction of the ECON 159 course lectures at Open Yale courses and YouTube and to the Game Theory 101 video series in hopes that people will find them useful.